Economist: FOR the system that is supposed to make it easier for people in the rich world to cut the greenhouse emissions of the poor, a “binary moment” has come. That, at the least, is the prediction of a banker with an interest in the future of the clean development mechanism (CDM). Like many others in the business, he foresees either buoyant growth or terminal decline for the arrangement designed to encourage financial transfers from long-established carbon emitters to emerging ones. On the …